Have any of you ever played around with the old Sun tachometers? The one with the black control box? I picked up a 12v 6 cyl. Sun for my '54 chev, but I'm not sure how they work or how to adjust it. There's a battery on the inside of the box. What's that all about? Can you still get the battery?
I've converted the car to a 12v negative ground. What do you think about building some kind of a voltage drop, and eliminating the battery all together?

I bought one of these at a swap meet a few years ago. 0-5000 RPM and the box says model EB-2, 6 cyl, 6 volts. I never opened up the box, just sent the whole thing to Williamsons Instrument Repair in Chester Arkansas, for conversion to 12v and calibration. Not sure if it had a battery in side or not, but I just took a look inside and there is no battery.

These tach & transmitter setups are actually pictured as an accessory in the mid-50s GMC master parts book.

What all did they do, go thru the entire thing? What did it set you back?

I'm really not sure what they did - I just asked them to convert it to 12 volt, test & repair as necessary, and calibrate for accuracy - This was about 3 yrs ago and it's still in the box they returned it in! I think it was about $120 (ouch) but I only paid about $20 for it originally.

All of those I have used used a couple of 1.35V mercury batteries. I don't think you can get them any more, but a couple of AA batteries work just fine. Joe

Anybody know the purpose of the battery? Not a big deal, just curious.

http://www.musclecartachs.com/docs/referencesun.htm
http://www.musclecartachs.com/docs/tachometerfaq.htm

OK you guys got me curious about A) what the batteries do and B) why there were none in mine when I got it returned from Williamson's, and C) what did I get for my $120. So I go to their web site and here is the explanation:






[This message has been edited by Jack (edited 05-15-2003).]

thanks for the info. Another mystery solved.